BVY 04-015, Technical Specification Proposed Change No. 257, Supplement No. 6 Regarding Implementation of Arts/Mella Calibration of APRM High Flux Flow Biastrip Function
| ML040490644 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png (DPR-028) |
| Issue date: | 02/10/2004 |
| From: | Thayer J Entergy Nuclear Northeast |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BVY 04-015 | |
| Download: ML040490644 (11) | |
Text
Entergy Nuclear Northeast
_Ajt Entergy Nuclear Operations, Inc.
Vermont Yankee 322 Governor Hunt Rd.
v-=P~r tfg P.
Aa O.
Box 157 Vernon, Vr 05354 Tel 802-257-771 1 February 10, 2004 BVY 04-015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
Subject:
Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)
Technical Specification Proposed Change No. 257 - Supplement No. 6 Implementation of ARTS/MELLLA at Vermont Yankee Calibration of APRM Hiah Flux Flow Bias Trip Function By letter dated March 20, 2003, as supplemented by letters dated March 31, 2003, April 17, 2003, June 11, 2003, July 21, 2003, and December 11, 2003, Vermont Yankee' (VY) proposed to amend Facility Operating License DPR-28 for the Vermont Yankee Nuclear Power Station by implementing an expanded power-to-flow operating domain based on the Average Power Range Monitor, Rod Block Monitor Technical Specifications/Maximum Extended Load Line Limit Analysis (ARTS/MELLLA) methodology. Based on recent discussions with the NRC staff, VY is supplementing its license amendment request (LAR) to clarify existing practices for the periodic calibration of the APRM High Flux Flow Bias trip function.
The calibration of the APRM High Flux Flow Bias trip units provides a periodic check of the actual trip setpoint. For this instrumentation, it is VY's practice to verify the trip unit setpoint during Technical Specification (TS)-required functional testing. The current TS in Table 4.1.1 requires that the trip function be functionally tested every three months. During surveillance testing, if the trip setting is found to be outside the specified leave-as-is zone, the trip unit is adjusted until the trip function occurs within the proper range. This constitutes a calibration of the trip unit and is consistent with the assumptions in VY's setpoint uncertainty calculation.
VY is hereby proposing that the LAR be supplemented with the change to TS that is provided herewith. TS Table 4.1.2 is clarified to specify that the High Flux APRM Flow Bias trip function is calibrated at a minimum frequency of every three months. A note is added to Table 4.1.2 to further clarify that the subject testing only involves calibration of the APRM trip units and is not Entergy Nuclear Vermont Yankee, LLC and Entergy Nuclear Operations, Inc. are the licensees of the Vermont Yankee Nuclear Power Station.
BVY 04-015 / Page 2 a complete check of the instrument loop. The calibration of the instrument loop is conducted during refueling outages because of the need to perform the surveillance under the conditions that apply during a plant outage. Otherwise, there is the potential for an unplanned transient if the surveillance were performed with the reactor at power. Attachment 1 to this letter provides a mark-up of the current TS and TS Bases pages indicating the proposed changes. Attachment 2 provides the retyped TS and TS Bases pages.
This supplement to the LAR does not change the scope or conclusions in the original application, nor does it change VY's determination of no significant hazards consideration. If you have any questions in this regard, please contact Mr. James DeVincentis at (802) 258-4236.
Sincerely, Jay.T y
SiteW e President STATE OF VERMONT
)
)ss WINDHAM COUNTY
)
Then personally appeared before me, Jay K. Thayer, who, being duly sworn, did state that he is Site Vice President of the Vermont Yankee Nuclear Power Station, that he is duly authorized to execute and file the foregoing document, and that the statements therein are true to the best of his knowledge and belief.
Sall' SAdsurn, Notiry Public My Commission Expires February 10, 2007 Attachments (2) cc:
USNRC Region I Administrator (w/o attachments)
(
A USNRC Project Manager - VYNPS U 3 IL!
Vermont Department of Public Service
I Docket No. 50-271 BVY 04-015 Attachment I Vermont Yankee Nuclear Power Station Proposed Technical Specification Change No. 257 - Supplement No. 6 ARTS/MELLLA Calibration of APRM High Flux Flow Bias Trip Function Marked-up Technical Specifications Pages
VYNPS TABLE 4.1.2 SCRAM INSTRUMENT CALIBRATION MINIMUM CALIBRATION FREQUENCIES FOR REACTOR PROTECTION INSTRUMENT CHANNELS Instrument Channel High Flux APRM Output Signal Output Signal (Reduced) (7)
Flow Bias LPRM (LPRM ND-2-1-104(80))
Group (1)
B B
B B(5)
Calibration Standard(4)
Minimum FrequencY(2 )
Heat Bala Heat Bala Standard Source Using TIP nce nce Pressure Once Every 7 Days Once.Every 7 Days fe Refueling Outage and Voltac High Reactor Pressure Turbine Control Valve Fast Closure High Drywell Pressure High Water Level in Scram Discharge Volume Low Reactor Water Level Turbine Stop Valve Closure First Stage Turbine Pressure Permissive (PS-S-14(A-D)')
Main Steam Line Isolation Valve Closure B
A B
B A
A A
Standard Standard Standard Water Lev Standard (6)
Pressure (6)
System Every 2,000 MWD/T average core exposure (8)
Pressure Source Once/Operating Cycle Pressure Source Every 3 Months Pressure Source Once/Operating Cycle
-el.
Once/Operating Cycle Pressure Source Once/Operating Cycle Refueling Outage Source Every 6 Months and After Refueling Refueling Outage I
Amendment No. a4, G4, a,
6.,
&, i
+1" 0
-. I.4, 212 27
VYNPS TABLE 4.1.2 NOTES
- 1.
A description of the three groups is included in the bases of this Specification.
- 2.
Calibration tests are not required when the systems are not required to be operable or are tripped.
If tests are missed, they shall be performed prior to returning the systems to an operable status.
- 3.
Deleted.
- 4.
Response time is not part of the routine instrument check and calibration, but will be checked every operating cycle.
S.
Does not provide scram function.
- 6.
Physical inspection and actuation.
.7. The IRM and SRM channels shall be determined to overlap during each startup after entering the STARTUP/HOT STANDBY MODE and the IRM and APRM channels shall be determined to overlap during each controlled shutdown, if not performed within the previous 7 days.
- 8.
The specified frequency is met if the calibration is performed within 1.25 times the interval specified, as measured from the previous performance.
Amendment No. GE, BdG, a@E, 212
.28
VYNPS BASES: 4.1 (Cont'd)
I
_o I
LPRM gain settings are determined from the local flux profiles measured by the Traversing Incore Probe (TIP) System.
This establishes the relative local flux profile for appropriate representative input to the APRM System.
The 2,000 megawatt-days per short ton (MWD/T) frequency is based on operating experience with LPRM sensitivity changes, and that the resulting nodal power uncertainty, combined with other identified uncertainties, remains less than the total uncertainty (i.e., 8.7t) allowed by the GETAB safety limit analysis.
< 'NRT #1>
Note: This page is not from current Technical Specifications, but is as proposed in PC-257, BVY 03-23, dated March 20, 2003.
Amendment No. 6S, 4-e, A-9-d 33a
INSERT #1 (insert the following into the Bases for TS 4.1.A)
The calibration of the APRM High Flux Flow Bias trip units provides a check of the actual trip setpoints. If the trip setting is found to be less conservative than accounted for in the appropriate setpoint calculation, but is not beyond the Allowable Value specified in Table 3.1.1, the channel performance is still within the requirements of the plant safety analysis. However, if the trip setting is found to be less conservative than the Allowable Value specified in Table 3.1.1, the channel should be declared inoperable. Under these conditions, the setpoint should be readjusted to be equal to or more conservative than accounted for in the appropriate setpoint calculation. The specified trip unit calibration frequency (i.e., every 3 months) is consistent with the assumptions of the VYNPS setpoint methodology and the reliability analysis of NEDC-30851-P-A, 'Technical Specification Improvement Analyses for BWR Reactor Protection System," March 1988.
Docket No. 50-271 BVY 04-015 Vermont Yankee Nuclear Power Station Proposed Technical Specification Change No. 257 - Supplement No. 6 ARTS/MELLLA Calibration of APRM High Flux Flow Bias Trip Function Re-typed Technical Specifications Pages
VYNPS TABLE 4.1.2 SCRAM INSTRUMENT CALIBRATION MINIMUM CALIBRATION FREQUENCIES FOR REACTOR PROTECTION INSTRUMENT CHANNELS Instrument Channel High Flux APRM Output Signal Output Signal (Reduced) (7)
Flow Bias LPRM (LPRM ND-2-1-104(80))
Group (1)
B B
B B (5)
Calibration Standard(4)
I High Reactor Pressure Turbine Control Valve Fast Closure High Drywell Pressure High Water Level in Scram Discharge Volume Low Reactor Water Level Turbine Stop Valve Closure First Stage Turbine Pressure Permissive (PS-5-14(A-D))
Main Steam Line Isolation Valve Closure B
A B
B B
A A
A Heat Balance Heat Balance Standard Pressure Source Using TIP System Standard Pressure Standard Pressure Standard Pressure Water Level Standard Pressure (6)
Pressure Source and Voltage Source Source Source Minimum Frequency (2)
Once Every 7 Days Once Every 7 Days Refueling Outage Every 3 Months (9)
Every 2,000 MWD/T average core exposure (8)
Once/Operating Cycle Every 3 Months Once/Operating Cycle Once/Operating Cycle Once/Operating Cycle Refueling Outage Every 6 Months and After Refueling Refueling Outage Source (6)
Amendment No. -14, GE~, 2-2,
-54, 61, z4&,
li, 186, 1-91, 212 27
VYNPS TABLE 4.1.2 NOTES
- 1.
A description of the three groups is included in the bases of this Specification.
- 2.
Calibration tests are not required when the systems are not required to be operable or are tripped.
If tests are missed, they shall be performed prior to returning the systems to an operable status.
- 3.
Deleted.
- 4.
Response time is not part of the routine instrument check and calibration, but will be checked every operating cycle.
- 5.
Does not provide scram function.
- 6.
Physical inspection and actuation.
- 7.
The IRM and SRM channels shall be determined to overlap during each startup after entering the STARTUP/HOT STANDBY MODE and the IRM and APRM channels shall be determined to overlap during each controlled shutdown, if not performed within the previous 7 days.
- 8.
The specified frequency is met if the calibration is performed within 1.25 times the interval specified, as measured from the previous performance.
- 9.
APRM trip unit calibration only.
Amendment No. GE, a84, 1911, 282 28
i te VYNPS BASES: 4.1 (Cont'd)
The calibration of the APRM High Flux Flow Bias trip units provides a check of the actual trip setpoints. If the trip setting is found to be less conservative than accounted for in the appropriate setpoint calculation, but is not beyond the Allowable Value specified in Table 3.1.1, the channel performance is still within the requirements of the plant safety analysis. However, if the trip setting is found to be less conservative than the Allowable Value specified in Table 3.1.1, the channel should be declared inoperable. Under these conditions, the setpoint should be readjusted to be equal to or more conservative than accounted for in the appropriate setpoint calculation.
The specified trip unit calibration frequency (i.e., every 3 months) is consistent with the assumptions of the VYNPS setpoint methodology and the reliability analysis of NEDC-30851-P-A, "Technical Specification Improvement Analyses for BWR Reactor Protection System," March 1988.
LPRM gain settings are determined from the local flux profiles measured by the Traversing Incore Probe (TIP) System.
This establishes the relative local flux profile for appropriate representative input to the APRM System.
The 2,000 megawatt-days per short ton (MWD/T) frequency is based on operating experience with LPRM sensitivity changes, and that the resulting nodal power uncertainty, combined with other identified uncertainties, remains less than the total uncertainty (i.e., 8.7%) allowed by the GETAB safety limit analysis.
Amendment No.
1, a84, 49a-33a